There is a system formed from an information processing apparatus (e.g., personal computer) connected to a printer. Some systems of this type comprise a spool unit which temporarily saves data (so-called intermediate code) of a format different from that of print data to be finally transmitted to the printer before the information processing apparatus generates print data to be transmitted to the printer. This system comprises a despool unit which generates, from data temporarily saved in the intermediate code format, print data to be finally transmitted to the printer, and a generation unit which generates a printer control command.
This system supports so-called variable printing which is replacement printing of variable data. As the DTP (Desk Top Publishing) technique advances and digital printing apparatuses prevail, variable printing enables output of document data customized for each customer.
When creating a customized document, the variable printing system generally lays out a container in document data. The container is a rendering region also called a field region for rendering contents (rendering contents such as an image and text). The variable printing system lays out containers in document data, and associates the layout with a database (associates the containers with various contents in the database).
As a result, the variable printing system can create desired customized document data (called a document template). The contents of the document data can be changed (variable) by properly switching (changing the association) contents in the containers in the customized document data. This document data is called a variable data document, and a printing system using the variable data document is a variable printing system.
These days, demands for short delivery periods and work requests for various products in small lots are increasing in the market. To make a profit while meeting the user demands, printing companies are seeking for cooperation between offset printing and POD (digital printing).
The POD stands for Print On Demand. The POD can print many copies and many jobs within a short delivery period without using a large-scale printing apparatus or system. The POD implements digital printing using electronic data by fully utilizing a digital image forming apparatus such as a digital copying machine or digital multifunction peripheral.
In the POD market suitable for large-lot printing, demand has arisen for variable printing partially including variable data, like direct mail. Offset presses popular in the POD market are excellent in printing permanent contents in a large lot, but are not suited to variable printing of changing print contents for each product.
This is because the offset press generally uses seven color inks and requires plate making work to make a physical plate for each ink. This raises the plate fixed cost, labor cost, and time cost. To the contrary, an electrophotographic printer, which is a kind of digital image forming apparatus (digital press), forms an image using an electrostatic latent image. The electrophotographic printer does not require any physical plate, unlike offset printing, is free from the fixed cost, and can easily cope with small-lot printing and variable printing.
However, since the print sheet size of the digital press is smaller than that of the offset press, the unit cost per finishing print sheet is higher. At present, the digital press is suited to small-lot printing and variable printing, whereas the offset press is suited to large-lot printing.
Japanese Patent Laid-Open No. 2005-260332 discloses a function of detecting imposition information on the imposition position and electronically cutting large-size image data on the basis of the imposition information in order to use offset printing image data in on-demand printing. Also, Japanese Patent Laid-Open No. 2005-260332 discloses a function of editing each cut image based on information on a designated output form.
In many cases, the above-mentioned system is requested to provide printed materials of document data including permanent pages with permanent contents, and variable pages with variable data whose contents change for each printed material. The offset press cannot print such document data because it is disadvantageous to make a press plate for each variable printing (variable data printing). Thus, variable printing must be done by the digital press.
However, when document data including variable pages are printed in a large lot, the cost rises because of the above-described reasons. To prevent this, an operator at the POD center must classify permanent and variable pages in document data into separate document data. The offset press prints the document data of the permanent pages, and the digital press prints those of the variable pages.
However, it is troublesome to the operator to divide, into separate document data, document data in which variable and permanent pages coexist complicatedly.